Convenient platform for quick prototyping. Houses a breadboard and an Arduino (R3, R4, Leonardo). Includes room for two built-in push buttons and three LEDs. 

I can connect the LEDs directly to the Arduino (or to the breadboard) because they have series resistors attached to them.

The Arduino does not need to be screwed down.

The LEDs and switches have one common ground wire.

Can be printed without supports.